Electromotive furniture drive

p0001The invention relates to an electromotive furniture drive of the type mentioned in the preamble of claim 1 for adjusting parts of a furniture relative to one another.

p0002Such furniture drives are generally known and serve, for example, as adjusting drives for adjusting parts of a slat grating relative to each other.

p0003By <patcit id="pcit0001" dnum="EP0372032B1"><text>EP 0 372 032 B1</text></patcit> A furniture drive of the type in question is known which has a drive means linearly movable along a linear axis of movement for pivoting a pivoting element which is pivotable about a pivot axis in the assembly position of the furniture drive with a part of the furniture to be adjusted. In the known furniture drive, the linearly movable drive means is formed by a spindle nut of a spindle drive, while the pivoting element is formed by a pivoting lever, which is non-rotatably connected to a pivot shaft which is operatively connected to the part of the furniture to be adjusted. In this case, the spindle nut loosens the end of the pivoting lever remote from the pivot shaft.

p0004Similar furniture drives are also available through <patcit id="pcit0002" dnum="DE3842078C2"><text>DE 38 42 078 C2</text></patcit>, <patcit id="pcit0003" dnum="EP0583660B1"><text>EP 0 583 660 B1</text></patcit>, <patcit id="pcit0004" dnum="DE10046750C1"><text>DE 100 46 750 C1</text></patcit> and <patcit id="pcit0005" dnum="DE10046752C1"><text>DE 100 46 752 C1</text></patcit> known.

p0005In the known furniture drives, the angular position of the pivoting lever relative to the linear axis of movement of the drive means changes during the adjusting movement. This results in the disadvantage that the effective length of the lever arm acting on the pivot shaft, that is to say the length of the component of the lever arm perpendicular to the linear axis of movement of the drive means, constantly changes during the adjusting movement so that the forces acting on the pivot shaft, Which is to be displaced, constantly changes during the adjusting movement and decreases with a reduction in the effective length of the lever arm. In this case, the sharper the angle between the linear axis of movement of the drive means and the longitudinal axis of the pivoting lever is, the more pronounced the adjusting force which can be exerted by the furniture drive on the part of the furniture to be adjusted. It is particularly disadvantageous here that the further the furniture drive approaches an end position of the adjusting movement, the angle, however, becomes more acute in which, however, the reaction force of the furniture acting on the furniture drive and thus the adjusting force is usually greatest.

p0006By <patcit id="pcit0006" dnum="DE10017978A1"><text>DE 100 17 978 A1</text></patcit> and <patcit id="pcit0007" dnum="DE10017979A1"><text>DE 100 17 979 A1</text></patcit> In the case of which the drive means is formed by a flexible traction means, for example in the form of a tension band, similar furniture drives are known in each case for the aforementioned furniture drives.

p0007By <patcit id="pcit0008" dnum="DE2614105A"><text>DE 26 14 105 A</text></patcit> Is an electromotive furniture drive for adjusting parts of a furniture relative to one another which has a drive means linearly movable along a linear axis of movement for pivoting a pivoting element which is pivotable about a pivot axis in the mounting position of the furniture drive with a part of the furniture to be adjusted. The furniture drive known from the publication also has means which hold the drive means during the adjusting movement in engagement with the pivoting element at the essentially fixed point along the linear movement axis, which guide elements have a guide element for the drive means designed in the manner of a cam disk, In the mounting position of the furniture drive. In the known furniture drive, the drive means is formed by a webbing which can be wound up by means of a winding device.

p0008The object of the invention is to provide an electromotive furniture drive of the type mentioned in the preamble of claim 1, which is simple in structure, robust and space-saving.

p0009This object is achieved by the teaching given in claim 1.

p0010The invention is based on the realization that the effective length of the lever arm of the pivoting element is changed by the fact that during the adjusting movement the point at which the drive means acts on the pivoting element moves along the linear axis of movement of the drive means. Accordingly, the invention is based on the idea of ​​providing means which hold the drive means in engagement with the pivoting element during the adjusting movement at a point which is essentially fixed in position along the linear axis of movement. In this way it is achieved that the effective length of the lever arm does not substantially change during the adjustment movement, so that the adjusting force which can be exerted by means of the furniture drive on the part of the furniture to be adjusted is essentially constant during the entire adjusting movement. Thus, during the entire adjustment movement, substantially uniform forces can be exerted on the part of the furniture to be adjusted, in particular also in the end positions of the adjusting movement. According to the invention, the guide element is designed as a toothed wheel or as a toothed segment, the drive means comprising a chain in such a way that a warp drive is formed. Furthermore, the teaching according to the invention provides that the linearly movable drive means is connected to a linearly movable drive element of a spindle drive or is formed by the linearly movable drive element of a spindle drive.

p0011The furniture drive according to the invention is simple and thus inexpensive to manufacture and robust in construction. It is suitable for adjusting any parts of a piece of furniture, but in particular for adjusting adjustable parts of a support device for a cushioning of a seat and / or lounge furniture, for example a slatted frame.

p0012A further development of the invention provides that the guide element has a substantially circular arc-shaped contour. In this embodiment, the guide element is particularly simple and thus inexpensive to produce.

p0013In the aforementioned embodiment, the guide element can extend over an angle of 360 ° or approximately 360 ° with respect to the pivot axis so that the guide element essentially has the contour of a full circle. A further development of the aforementioned embodiment provides that the guide element is designed essentially as a circular segment, in particular a quarter circular segment. Such an extension of the guide element in the pivoting direction is generally sufficient to ensure an engagement of the drive means on the pivoting element at a point which is essentially fixed in position along the linear axis of movement during the adjusting movement.

p0014Another development of the invention provides that the guide element has a substantially curvilinear contour with a spacing of the boundary surface of the contour from the pivot axis that changes at least in sections in the circumferential direction of the guide element. In this embodiment, the guide element and the drive means form a crank drive. According to the curve shape of the guide element, the angular velocity at which the pivoting element is pivoted changes at the constant speed of the drive means along the linear axis of movement.

p0015According to the respective requirements, the drive means can be designed as a traction means or a pressure medium, as is provided for further developments.

p0016According to other developments of the teaching according to the invention, the drive means can be flexible or essentially rigid.

p0017An extremely advantageous development of the teaching according to the invention provides that the drive means, at its surface which is in engagement with the guide element in the assembled position of the furniture drive, has toothing for cooperation with a toothing of the guide element which is essentially complementary thereto. In this embodiment, the guide element and the drive means cooperate in the manner of a toothed drive. This embodiment is particularly simple and thus inexpensive to produce. In addition, it is particularly robust and suitable for applying large forces.

p0018In principle, the guide element can be formed by a separate component which is connected non-rotatably to the pivoting element. The construction of the furniture drive according to the invention can, however, be further simplified by the fact that the guide element is formed integrally with the pivoting element or is formed by the pivoting element, as is provided by a further development of the inventive teaching.

p0019According to a development of the invention, the linearly movable drive element of the spindle drive can be a spindle nut arranged in a rotational direction and movable in the axial direction on a rotationally drivable spindle.

p0020However, in a kinematic reversal of the aforementioned embodiment, the linearly movable drive element of the spindle drive can also be a spindle which is movable in its axial direction and is mounted in a rotationally fixed manner and on which a stationary, rotationally drivable spindle nut is arranged.

p0021Another advantageous development of the teaching according to the invention provides that the drive means is fixed to the pivoting element or the guide element.

p0022An electromotorically adjustable support device for an upholstery of a seat and / or lounge furniture, in particular a mattress of a bed, is disclosed in claim 14.

p0023The invention is explained in more detail below with reference to the accompanying drawing, in which exemplary embodiments are shown.

p0024It shows:<dl id="dl0001" compact="compact"><dt>FIG</dt><dd>A top view of a support device according to the invention configured as a slatted frame, which is provided with an exemplary embodiment of a furniture drive according to the invention,</dd><dt>FIG</dt><dd>A section along a line II-II in FIG <figref idrefs="f0001">FIG</figref>,</dd><dt>FIG</dt><dd>In the same representation as <figref idrefs="f0002">FIG</figref> in opposite <figref idrefs="f0002">FIG</figref> On a larger scale <figref idrefs="f0002">FIG</figref> In the area of ​​the furniture drive.</dd></dl>

p0025In the figures of the drawing, identical or corresponding components are provided with the same reference symbols.

p0026In <figref idrefs="f0001">FIG</figref> An exemplary embodiment of a support device 2 according to the invention is shown, which in this exemplary embodiment is designed as a slatted frame and has a frame 4 to which a stationary middle support part 6 is connected. A leg support part 8 is connected to the central support part 6 in an articulated manner and can be pivoted about a horizontal pivot axis. A leg support part 10 is pivotably connected to the end remote from the middle support part 6 and pivotable about a horizontal pivot axis. With the end of the central support part 6 facing away from the leg support part 8, an upper body support part 12 is articulated and can be pivoted about a horizontal pivot axis. A head support part 14 is pivotally connected to the end remote from the middle support part 6 and pivotable about a horizontal pivot axis. The manner in which the support parts 6 to 14 are connected to one another is generally known and is therefore not explained in detail here.

p0027On their upper side, the support parts 6 to 14 are provided with resilient slats, only one of which is provided with the reference character 16 in the drawing. The slats 16 serve for the resilient support of a cushioning of a sitting and / or lounge furniture, for example a mattress of a bed, which is not shown in the drawing and which is supported by means of the support device 2.

p0028The support device 2 according to the invention is provided with a first exemplary embodiment of a furniture drive 18 according to the invention which, in this exemplary embodiment, serves for adjusting the upper body support part 12 and the head support part 14 relative to the middle support part 6. In this exemplary embodiment, the furniture drive 18 is accommodated in a hollow side rail 19 of the central support part 6.

p0029<figref idrefs="f0002">FIG</figref> 11 is a sectional view taken along a line II-II in FIG <figref idrefs="f0001">FIG</figref>.

p0030<figref idrefs="f0003">FIG</figref> Shows the furniture drive 18 according to the invention in FIG <figref idrefs="f0002">FIG</figref> Larger scale. The furniture drive 18 comprises a fixed to a wall of the side member 19 electric motor 20, which via a Getri ebeanordnung 22 is in rotary drive connection with a stationary, rotationally drivable spindle 24 of a spindle drive. A spindle nut 26 is arranged on the spindle 26 so as to be rotatable and movable in the axial direction of the spindle 24 in the direction of a double arrow 28. Corresponding to the direction of rotation of the output shaft of the electric motor 20 and thus the direction of rotation of the spindle 24, the spindle nut 26 moves along a linear movement axis 30 in FIG<figref idrefs="f0003">FIG</figref> Left or right.

p0031In this exemplary embodiment, the support device 2 has an adjustment fitting 32 according to the invention, which in this exemplary embodiment has a pivot shaft 36 which is pivotally mounted on the frame 4 of the support device 2 about a pivot axis 34 and with which a pivot lever 38 is connected in a rotationally fixed manner. The pivot lever 38 is connected to the upper body support part 12 and the head support part 14 in such a way that the upper body support part 12 and the head support part 14 are pivoted about the pivot axis 34 when the pivot shaft 36 is pivoted. The adjusting fitting 32 according to the invention has a pivoting element which is non-rotatably connected to the pivot shaft 36 and is designed as a gear segment 40 in this exemplary embodiment and is in engagement with a flexible traction means in the form of a chain 42, one end of which is attached to the gear segment 40 and the other end thereof On the spindle nut 26. In this exemplary embodiment, the chain 42 forms a drive means of the furniture drive 18 which is movable along the linear movement axis 30.

p0032According to the invention, means are provided which, in the embodiment according to FIG <figref idrefs="f0001">FIG</figref> That is to say the chain 42, during the adjusting movement on a point P which is essentially fixed in position along the linear axis of movement 30, with the gear segment 40 forming the pivoting element. In the exemplary embodiment according to FIG<figref idrefs="f0001">FIG</figref> These means are formed in that the gear segment 40 is designed as a guide element for the chain 42, which is designed in the manner of a cam disk. In this exemplary embodiment, the gear segment 40 has a substantially circular arc-shaped contour and is designed as a quarter-circle segment. During the adjusting movement, the gear segment 40 pivots about the pivot axis 34, the wrap angle of the chain 42 changing around the gear segment 40. However, the chain 24 is always held in engagement with the toothed wheel segment 40 at the point P which is essentially stationary along the linear axis of motion 30 so that the effective length of the chain,<figref idrefs="f0003">FIG</figref> Which is symbolized by a dash-dotted line 44 with which the chain 42 engages on the pivot shaft 36, remains essentially unchanged during the adjustment movement.

p0033The mode of operation of the invention. Furniture drive 18 is as follows:

p0034For adjusting the upper body support part 12 and the head support part 14 from an initial position of the adjusting movement, which is not shown in the drawing, in which the upper body support part 12 and the head support part 14 together with the middle support part 6 span a horizontal support plane, <figref idrefs="f0002">FIG</figref> , The electric motor 20 drives the spindle 24 via the gear arrangement 22 in such a way that the spindle nut 26 is moved into the spindle 24, <figref idrefs="f0003">FIG</figref> To the right. Here, the chain 42 is engaged with the toothing of the gear segment 40, so that the gear segment 40,<figref idrefs="f0003">FIG</figref> To the right in <figref idrefs="f0003">FIG</figref> About the pivot axis 4 in the clockwise direction. On account of the rotationally fast connection between the pivotal lever 38 and the pivot shaft 36, the pivotal lever 38 in FIG<figref idrefs="f0003">FIG</figref> In the clockwise direction, so that the upper body support part 12 and the head support part 14 in FIG <figref idrefs="f0001">FIG</figref> In the clockwise direction.

p0035During the adjustment movement, the chain 42 is always in engagement with the gear segment 40 at the point P so that the effective length of the lever arm 44, with which the chain 42 engages on the pivot shaft 36, does not change during the adjusting movement. Since the effective length of the lever arm 44 does not change during the adjusting movement, the adjusting force acting on the upper body support part 12 and the head support part 14 which is applied by means of the furniture drive 18 substantially does not remain substantially during the adjusting movement at constant drive torque of the electric motor 20. Thus, by means of the furniture drive 18 according to the invention, essentially constant forces can be exerted on the upper body support part 12 and the head support part 14 during the entire adjustment movement.

p0036FIG. 4 shows a second exemplary embodiment of a furniture drive 18 according to the invention, which is different from the exemplary embodiment according to FIG <figref idrefs="f0003">FIG</figref> In that the drive means instead of a chain 42 has a toothed rack 56 which is formed on the end of the spindle nut 26 facing the gear segment 40. The toothed rack 56 and the spindle nut 26 can, for example, be formed in one piece by a plastic molding. The toothed rack 56 has a toothing which is essentially complementary to the toothing of the toothed wheel segment 40. In this exemplary embodiment, the toothed rack 56 is held in engagement with the toothed wheel segment 40 during the adjusting movement on a point P which is essentially fixed in position along the linear axis of movement 30, so that the length of the lever arm with which the toothed rack 56 engages on the pivot shaft 36, Substantially.

p0037The furniture drive 18 according to the invention can be produced simply and inexpensively and is robust in construction.